Sand cores as used for molding metal products are placed in casting cavities and openings to form passageways or hollow portions in the casting. Such cores are formed by combining sand and a binder substance, such as synthetic resins, in a core making machine having patterns or dies to shape the core. During the formation of such cores, small, fin-like extensions, known as "fins" or "flash" often develop along the junction between the core-making dies. These undesired fins must be removed or at least substantially reduced to such an extent that they do not impair the formation of the finished metal product during the casting process.
In the past, removal of the undesired fins has been accomplished manually. That is, one would normally pick up a newly formed core and scrape the fins with a wire brush or a small rigid tool, such as a file or knife to knock the fins off. This is not only time-consuming and costly, but the manual core handling often leads to the eventual destruction of a small percentage of cores due to dropping, too vigorous handling, or cracks induced during the fin knock-off procedure.
In prior attempts to clean such cores, a falling curtain of core cleaning material, such as metal shot or grit has been attempted. This cleaning technique has been demonstrated as effective on a small, batch type test operation. However, once the metal shot or grit is used, it becomes mixed with loosened sand particles and cannot be reused as an effective core cleaning material in the mixed condition due to the cushioning effect of the sand. Problems in attempts at separating the loosened sand from the metal shot or grit and transferring same to provide a workable, continuous core-cleaning system were not solved, thus leading to an eventual disregard of the metal shot curtain technique for cleaning sand cores.
Accordingly, the present invention provides a complete, continuous core-cleaning system and apparatus for economically, quickly and reliably eliminating or at least removing to a desired extent all of the fins from sand cores.